HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Lee, L. S. Articles by Turco, R. F. Search for Related Content PubMed PubMed Citation Articles by Lee, L. S. Articles by Turco, R. F. Agricola Articles by Lee, L. S. Articles by Turco, R. F. Related Collections Soil Microbiology Microbial Processes Organic Compounds Agricultural Pesticides

TECHNICAL REPORTS

Organic Compounds in the Environment

Degradation of N,N'-Dibutylurea (DBU) in Soils Treated with only DBU and DBU-Fortified Benlate Fungicides

Department of Agronomy, Purdue University, West Lafayette, IN 47907-1150

^* Corresponding author (lslee{at}purdue.edu).

Received for publication January 9, 2004. N,N'-dibutylurea (DBU) is a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed to cause crop damage after the use of Benlate 50 DF fungicide (DuPont, Wilmington, DE). Our research focused on DBU persistence after application into soil. We assessed DBU persistence on direct application of DBU (carbonyl–¹⁴C) at two concentrations (0.08 and 0.8 µg DBU kg^–1) to seven soils and two potting mixes in soil microcosms incubated at various combinations of soil water potential (–0.03 or –0.1 MPa) and temperature (23, 33, 44°C). For two soils at a subset of treatment variables we assessed DBU persistence in the presence of Benlate DF and SP fungicide formulations. Parent compounds, metabolites, and ¹⁴CO₂ were tracked using chromatographic analysis with radioassay and UV detection, liquid scintillation counting, and post-extraction oxidation of the soil. DBU degradation was primarily microbial and for most soil–treatment combinations, half-lives were less than 2 wk. DBU degradation was retarded at the lower soil water potential and enhanced at 33°C. In the presence of the formulation, DBU degradation was slower for one soil type. The longest half-life observed in any case was less than 7 wk; therefore, long-term persistence of DBU applied to soils through a Benlate application is very unlikely.

Abbreviations: DBU, N,N'-dibutylurea • HPLC, high performance liquid chromatography • LSC, liquid scintillation counting

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2004 33: 1589-1599. [Full Text]